Effect of 2% Topical Lidocaine Gel on Discomfort from Electrical Stimulation During Nerve Conduction Studies- A Prospective Double-Blind Placebo-Controlled Study

Purpose

Procedure discomfort can limit electrodiagnostic studies. Reducing discomfort can maximize the benefits of these diagnostic tools. This study targeted the discomfort associated with nerve conduction studies (NCS).

Patients and Methods

This was a prospective randomized double-blind placebo-controlled study comparing the effect of topical lidocaine gel (2%) versus analgesic-free lubricant gel (K-Y gel) on pain perception during NCS. Sequential patients (n=130) referred for routine NCS participated in the study. We applied 1 mL of lidocaine gel to one palm, and 1 mL of K-Y gel to the other as a control. After 20-45 min of application, graded increments of electrical stimulation intensity were delivered to record the median and ulnar mixed palmar nerve responses. Patients were then asked to score the degree of pain felt from electrical stimulation over each palm using the Wong-Baker Faces Pain Scale (WBFPS) and the Numeric Rating Scale (NRS), independent of baseline pain.

Results

Mean WBFPS and NRS scores for lidocaine-treated palms were significantly lower than those for controls using parametric paired t-test (3.79 vs 4.37 and 3.35 vs 3.78 respectively, all p-values<0.05). Subgroup analysis showed a significant decrease in mean scores in females, patients aged ≤50 years, patients without a history of previous NCS, and patients without comorbidities (all p-values<0.05). Median scores using nonparametric Wilcoxon ranked test also showed statistically significant differences (all p-values<0.05).

Conclusion

The results indicate that topical lidocaine 2% gel reduces discomfort associated with NCS. However, despite the statistical significance, clear clinical significance may be lacking. Clinical implementation may be considered for the subgroups that showed the greatest benefit. Further studies that incorporate more efficient drug delivery methods may yield better results.

Rationale and design of a multicenter randomized clinical trial of vestibulodynia: understanding pathophysiology and determining appropriate treatments (vestibulodynia: UPDATe)

BACKGROUND

Limited data are available to establish evidence-based management protocols for vestibulodynia (VBD), a chronic vulvar pain condition that affects approximately 14 million women in the U.S. For the purposes of the study, our group subdivided VBD subtypes that may benefit from different types of treatment: 1) VBD peripheral (VBD-p), characterized by pain localized to the vulvar vestibule and 2) VBD central (VBD-c), characterized by VBD alongside one or more other chronic overlapping pain conditions (e.g. irritable bowel syndrome, temporomandibular disorder, and fibromyalgia syndrome) that affect remote body regions. Here, we describe the rationale and design of an NIH-funded multicenter clinical trial comparing the effectiveness of topical and/or systemic medication for alleviating pain and normalizing pain- relevant biomarkers among women with VBD-p and VBD-c.

METHODS

Participants will be randomly assigned to one of four parallel arms: peripheral treatment with 5% lidocaine + 0.5 mg/ml 0.02% oestradiol compound cream + oral placebo pill, 2) central treatment with the tricyclic antidepressant nortriptyline + placebo cream, 3) combined peripheral cream and central pill treatments, or 4) placebo cream and placebo pill. The treatment phase will last 16 weeks, with outcome measures and biomarkers assessed at 4 time points (0, 8, 16, and 24 weeks). First, we will compare the efficacy of treatments in alleviating pain using standardized tampon insertion with a numeric rating scale and self-reported pain on the short form McGill Pain Questionnaire. Next, we will compare the efficacy of treatments in improving perceived physical, mental, and sexual health using standardized questionnaires. Finally, we will measure cytokines and microRNAs in local vaginal and circulating blood samples using multiplex assays and RNA sequencing, and determine the ability of these biomarkers to predict treatment response.

CONCLUSION

This is the first multicenter randomized controlled trial to evaluate the efficacy of peripherally and centrally acting medications currently used in clinical practice for treating unique VBD subtypes based on distinct clinical and biological signatures.

ADMINISTRATIVE INFORMATION

Vestibulodynia UPDATe is a multi-centre, two-by-two factorial designed randomized, double-blind, placebo-controlled trial registered at clinical trials.gov (NCT03844412). This work is supported by the R01 HD096331 awarded to Drs. Nackley, Rapkin, Geller and Carey by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).Key messagesPeripheral lidocaine and oestradiol and centrally-targeted nortriptyline medications are used for the treatment of pain in women with VBD, but there is a lack of data from well-powered RCTs.This two-by-two factorial RCT will test the efficacy of these medications in VBD subtypes characterized by distinct clinical characteristics and biomarker profiles.We hope that results will provide clinicians with scientific evidence of therapeutic efficacy in distinct VBD subtypes in an effort to direct and optimize treatment approaches.

Comparison of the onset, depth, and duration of cutaneous anesthesia between topical 10% lidocaine and EMLA creams: A randomized, intraindividual, comparative trial

BACKGROUND

The eutectic mixture of local anesthetics (EMLA) is an effective cutaneous anesthetic, although its application is time consuming and poses a risk of methemoglobinemia. Currently, the efficacy of topical 10% lidocaine cream is unclear.

OBJECTIVE

To compare the onset, anesthesia depth, and duration of topical 10% lidocaine and EMLA cream.

METHODS

The randomized, split-body, comparative trial performed on 40 participants who received a topical 10% lidocaine cream or EMLA on forearms for 15-150 min. Pain was stimulated using a 21-gauge needle insertion and evaluated with the Verbal Pain Score. Adverse effects were recorded.

RESULTS

EMLA conferred significantly better efficacy than 10% lidocaine (p < 0.001). For acceptable pain at 4-mm depth, the minimal application times were 40.88 and 45.38 min of EMLA and 10% lidocaine creams, respectively. With 60/120-min application, the maximal needle-insertion depths with acceptable pain were 6.61/9.47 mm (EMLA) and 6.01/8.94 mm (10% lidocaine). EMLA's anesthetic effect showed an early increase after removal which was sustained for 60-90 min. Both creams caused adverse effects, with EMLA showing higher proportions, although the differences were statistically insignificant.

CONCLUSION

The efficacy of EMLA was superior to 10% lidocaine cream, especially regarding anesthesia onset and duration.

Impact of intravenous and topical lidocaine on clinical outcomes in patients receiving propofol for gastrointestinal endoscopic procedures: a meta-analysis of randomised controlled trials

BACKGROUND

The efficacy of i.v. or topical lidocaine as an anaesthesia adjunct in improving clinical outcomes in patients receiving gastrointestinal endoscopic procedures under propofol sedation remains unclear.

METHODS

Electronic databases (MEDLINE, EMBASE, and Cochrane Library) were searched for RCTs comparing the clinical outcomes with or without lidocaine application (i.v. or topical) in patients receiving propofol for gastrointestinal endoscopic procedures from inception to 29 March 2021. The primary outcome was propofol dosage, while secondary outcomes included procedure time, recovery time, adverse events (e.g. oxygen desaturation), post-procedural pain, and levels of endoscopist and patient satisfaction.

RESULTS

Twelve trials (1707 patients) published between 2011 and 2020 demonstrated that addition of i.v. (n=7) or topical (n=5) lidocaine to propofol sedation decreased the level of post-procedural pain (standardised mean difference [SMD]=-0.47, 95% confidence interval [CI]: -0.8 to -0.14), risks of gag events (risk ratio [RR]=0.51, 95% CI: 0.35-0.75), and involuntary movement (RR=0.4, 95% CI: 0.16-0.96). Subgroup analysis demonstrated that only i.v. lidocaine reduced propofol dosage required for gastrointestinal endoscopic procedures (SMD=-0.83, 95% CI: -1.19 to -0.47), increased endoscopist satisfaction (SMD=0.75, 95% CI: 0.21-1.29), and shortened the recovery time (SMD=-0.83, 95% CI: -1.45 to -0.21). Intravenous or topical lidocaine did not affect the incidence of oxygen desaturation (RR=0.72, 95% CI: 0.41-1.24) or arterial hypotension (RR=0.6, 95% CI: 0.22-1.65) and procedure time (SMD=0.21, 95% CI: -0.09 to 0.51).

CONCLUSION

This meta-analysis demonstrated that i.v. or topical lidocaine appears safe to use and may be of benefit for improving propofol sedation in patients undergoing gastrointestinal endoscopic procedures. Further large-scale trials are warranted to support our findings.

Less Exposure for Health Care Workers, More Comfort for Patients During COVID-19 Swab Testing

BACKGROUND

Nasopharyngeal (NP) and oropharyngeal (OP) swab sampling for coronavirus disease 2019 (COVID-19) diagnosis may lead to droplet and/or airborne particle transmission and increase the exposure risk for health care workers (HCWs). However, there is limited evidence for effective methods to reduce occupational exposure from NP and OP swab sampling. This study aimed to reduce droplet-forming responses (DFRs) and the related exposure risk of NP and OP swab sampling by administering 10% lidocaine spray (LS) to the NP and OP areas prior to conducting swab tests.

METHODS

This quasi-experimental study was conducted with 100 patients who presented to our tertiary care hospital with symptoms of COVID-19 between December 1 and 15, 2020. First, NP and OP swabbings were performed on each patient. Thereafter, LS was applied to the OP and NP regions, and the swab samples were taken once again. Frequency of DFRs and real-time polymerase chain reaction (RT-PCR) test results before and after LS application were recorded for comparison. In addition, the cycle threshold (Ct) was used as a proxy indicator for SARS-CoV-2 viral load in COVID-19 positive cases.

FINDINGS

Significant differences in OP DFR frequencies before and after LS intervention were found (37% and 9%, respectively), as well as before and after NP DFR (31% and 18%, respectively). The mean Ct values for the positive samples did not differ before and after applying LS.

CONCLUSION

Our results suggest that applying LS to the OP and NP area prior to swab testing reduces DFR frequencies without affecting (RT-PCR) test results for SARS-CoV-2 and may increase patient and practitioner comfort.

Analgesic effect of topical lidocaine is enhanced by cold atmospheric plasma pretreatment in facial CO2 laser treatments

BACKGROUND

Topical anesthesia is widely used in many dermatological and cosmetic procedures. Nevertheless, the stratum corneum serves as the skin barrier, impedes the transdermal drug delivery greatly, and results in insufficient analgesia. Cold atmospheric plasma (CAP) has been researched as a transdermal drug delivery promoter with ex vivo experiments for a few years, while clinical trials are scarce.

AIMS

To assess the efficacy and safety of CAP as a pretreatment to improve the transdermal absorption of topical anesthetic cream before the CO₂ laser treatment for postacne scars in the human body.

PATIENTS/METHODS

Twenty patients, seeking full facial laser treatment for atrophic acne scars, underwent a randomized split-face study. One side of the face was pretreated by CAP before topical anesthetic cream was applied, and the other side was applied with topical anesthetic cream only as control. After that, the subjects went through full-face fractional CO₂ laser treatment of postacne scars. They were asked to score the pain on a visual analogue scale (VAS) after the laser treatment to measure the anesthesia effects which indicates the transdermal absorption of the cream. Possible adverse effects of the plasma were recorded during the pretreatment including associated pain, heat, erythema, and edema.

RESULTS

The VAS score of the treated side was statistically lower (5.1 ± 2.1) compared with the nontreated side (6.3 ± 1.9), with a mean difference of 1.3 (95% confidence interval [CI], 0.6-1.9; P < .0001). No severe adverse event was reported, and all the disturbing sensations and symptoms (pain, heat, and edema) were evaluated as mild with no mean score surpassing 4.0.

CONCLUSION

Plasma pretreatment of 5 minutes before topical anesthetic cream application gives significant pain reduction during the laser procedures, showing the potential effects of CAP on promoting transdermal drug delivery, with no obvious adverse effects reported.

Fatal collapse due to autonomic dysreflexia during manual self-evacuation of bowel in a tetraplegic patient living alone: lessons to learn

Background

To identify areas for improvement, the National Health Service in England mandates the review of case reports of patients who have died, which should be translated into improved care for other patients.

Case report

A 49-year-old Caucasian man sustained C-7 tetraplegia in a motorcycle accident in 1992. In 2009, he developed seizures and collapsed in the lavatory on a number of occasions during manual self-evacuation of his bowel. A 24-hour electrocardiogram recording at that time showed sinus rhythm with a maximum heart rate of 97 and a minimum of 39 beats per minute; there were no significant arrhythmias that could have contributed to his episodes of collapse. In 2015, the patient again collapsed while performing manual evacuation of his bowel; on this occasion, he did not suffer a seizure. He was found unresponsive in the bathroom by his daughter, who contacted the emergency services. He recovered consciousness on arrival at the Accident and Emergency Department. A noncontrast computed tomography scan of his head revealed no acute intracranial pathology. In 2016, he suffered a fatal collapse in the lavatory, again while performing manual bowel evacuation. At autopsy, no other significant disease was found that might have caused death, and given the clinical history, the cause of death was recorded as autonomic dysreflexia.

Conclusion

There were delays in 1) recognizing that his episodes of collapse in the lavatory were due to autonomic dysreflexia induced by manual bowel evacuation; 2) recommending the prior application of topical 2% lidocaine jelly to prevent or limit autonomic dysreflexia occurring during manual bowel evacuation; and 3) considering alternative bowel management such as stimulant laxatives, transanal irrigation, or colostomy, which could have prevented the occurrence of autonomic dysreflexia caused by manual evacuation.

5% Lidocaine-medicated plaster for the treatment of chronic peripheral neuropathic pain: complex regional pain syndrome and other neuropathic conditions

Objectives

Chronic neuropathic pain and chronic complex regional pain syndrome (CRPS), in particular, are debilitating and difficult-to-treat conditions that have a strong impact on patient’s quality of life. The aim of this study was to evaluate the effectiveness of 5% lidocaine-medicated plaster as add-on therapy in patients with chronic peripheral neuropathic pain conditions, including CRPS.

Patients and methods

This was a single-center, prospective, observational study set in a specialized pain unit of a tertiary hospital in Spain. A total of 56 patients with long-standing peripheral neuropathic pain, ten of them with CRPS, received 5% lidocaine-medicated plaster as add-on analgesic therapy for 6 months.

Results

After 6 months of treatment, a ≥50% reduction in pain intensity was attained by 75% of patients, as measured by numeric rating scale (NRS) for pain. The average NRS score was reduced by 61% (4.7 points), from a baseline mean score of 7.8 to an end point mean score of 3.1. Marked improvements were also observed in the CRPS group: six out of ten patients achieved a ≥50% reduction in NRS score, and the average NRS score for patients with CRPS was reduced by 51% (4.0 points), from a baseline mean score of 7.9 to an end point mean score of 3.9. The improvements in pain intensity were partially translated into a decrease in disability index and in anxiety levels.

Conclusion

5% Lidocaine-medicated plaster may be useful as add-on therapy for a number of peripheral neuropathic pain conditions, including CRPS.

Cognitive function in older patients with postherpetic neuralgia

BACKGROUND AND AIMS

Neuropathic pain has been shown to be accompanied by cognitive impairment, but the specific impact of postherpetic neuropathic pain on cognitive processes has not been explored. This study aims to evaluate the impact of pain on several domains of cognition in older patients with postherpetic neuralgia (PHN).

METHODS

This cross-sectional study (clinicaltrial.gov NCT 00989040) included 84 individuals after signature of informed consent.

PARTICIPANTS

42 patients with PHN and 42 healthy volunteers. Of the 42 PHN patients, 21 received systemic treatment (antidepressants, anticonvulsants, opiates) and 21 had topical treatment with the 5% lidocaine medicated plaster. All participants performed a panel of four cognitive tests: reaction time, semantic memory, decision-making, and visual memory (Cantab, Cambridge).

RESULTS

Forty men and 44 women with a mean age of 72 ± 8 years participated. Each PHN patient was matched by age and gender with a healthy volunteer. Vigilance, decision-making, and semantic memory were significantly impaired (P < 0.05) in patients on systemic treatment, especially with antidepressants, while no significant changes were noted between the lidocaine plaster group and their matched controls of healthy volunteers.

CONCLUSION

This study shows the deleterious effect of systemic PHN treatment on several domains of cognition. Cognitive impairment associated with pain and antidepressants may be reversed by topical pain management. Topical treatment with 5% lidocaine medicated plaster is a valuable alternative for pain alleviation and maintains cognitive integrity in this vulnerable population.

Differential effects of a 5% lidocaine medicated patch in peripheral nerve injury

INTRODUCTION

We examined the effect of topical lidocaine on the function of small and large fibers in patients with peripheral neuropathic pain due to traumatic or postoperative nerve injury.

METHODS

In an open-label study, 24 patients were treated with a 5% lidocaine patch for up to 12 weeks. We recorded contact heat evoked potentials (CHEPs) and performed quantitative sensory testing (QST) before and after treatment with the contralateral side as control.

RESULTS

Twenty-one patients (mean age 47.6 ± 13.5 years) completed the study. Lidocaine increased cold pain threshold (P = 0.04) and reduced CHEP amplitude (P = 0.007) with no effect on other QST parameters. Patients responding to treatment had less cold detection deficit on the affected side and had a larger increase in cold pain detection threshold following treatment than nonresponders.

CONCLUSIONS

Controlled trials are warranted to further understand the mechanisms mediating the effects of topical lidocaine.

Life-threatening anaphylactic reaction after the administration of airway topical lidocaine

A 9-year-old boy who developed a life-threatening anaphylaxis reaction of the airway and subsequent dyspnea and circulation collapse because of instilled the topical lidocaine into the airway within 2 min before performing flexible bronchoscopy (FB). FB revealed swollen airway mucosa and extensive foamy secretion that severely compromised the ventilation lumen. Rapid detection with FB and immediate resuscitation, including prompt administration of epinephrine, volume expander, and positive pressure ventilation with pure oxygen via an endotracheal tube, were successfully save the patient's life.